1. Field of Invention
The present invention relates to a method of controlling an integrated circuit (IC) manufacturing procedure, and more particularly relates to a method of controlling a result parameter of an IC manufacturing procedure.
2. Description of Related Art
As the linewidth of IC device becomes smaller, the control of its properties gets more important. A characteristic value of an IC device usually relates to a plurality of processes in its manufacturing procedure, while the processes include a plurality of variables correlated with the characteristic value that have a number at least equal to the number of the processes. The variables are the key for controlling the characteristic value of the IC device.
One process control method as a self-correction method is provided in the prior art. The standard values of respective variables in combination corresponding to the target value of the result parameter are determined first. The respective processes correlated with the result parameter are controlled such that the difference between the real value of each variable and the standard value of the same is minimized, thereby making the value of the result parameter close to the target value of the same.
In an advanced process control (APC) method in the prior art, after the value of a variable of a process is found to have a substantial deviation, a variable of a subsequent process is adjusted according to the operator's experience to directly compensate the deviation of the variable of the former process. For example, in an IC manufacturing procedure including a deposition process and a later CMP process, the CMP-removed thickness is increased if the deposition thickness is overly large, or is decreased if the deposition thickness is overly small.
Since the above APC method utilizes adjustment of a variable of the subsequent process to directly compensate the deviation of a variable of the former process, it can only be applied to a manufacturing procedure where all variables correlated with the property to be controlled have the same physical quantity but cannot be applied to one where the variables correlated with the property to be controlled include different physical quantities, for example, a manufacturing procedure where the variables include the thickness of a film, an implantation concentration and temperature. Therefore, the application of the above APC method is much limited.